She arrived at the ceremony dressed in a black hat and scarlet coat and was joined by her parents Carole and Michael and the prince's private secretary Jamie Lowther-Pinkerton.

Junior Under Officer Angela Laycock, who is in the prince's Blenheim Platoon, earlier said the prince was not regarded any differently by his fellow cadets.

Miss Laycock, 24, said: "He's just a normal guy that gets stuck in like everybody else."

On riot training he had been "grabbing potatoes and lobbing them at the force protection people just like the rest of us," she said.

Major General Peter Pearson, Commandant of Sandhurst, said the prince had undergone the same gruelling regime as other trainee officers.

Becoming an officer "takes a lot of hard work", he said.

The prince has chosen to join the Household Cavalry's Blues and Royals alongside his brother Prince Harry, who graduated from Sandhurst earlier this year.

Both princes have indicated they are prepared to fight in zones of conflict.

The Prince has expressed a wish to serve in combat

Major General Sebastian Roberts, general officer commanding the Household Division and Prince William's new boss, indicated it was possible that the prince could be deployed to a conflict zone.

"Of course there are special factors for William, but nothing should be ruled in or out," he said.

He added that the prince had done "very well" at the military academy in Camberley, Surrey.

The prince will now spend four months at Bovington Camp in Dorset, training to become a troop commander in an armoured reconnaissance unit.

Unlike Prince Harry who will continue as a "career soldier", Prince William will go on to spend time with both the RAF and the Royal Navy on familiarisation attachments to prepare him for his future role.

He will increasingly carry out public engagements in parallel to his military career.